Peter Shaffer’s plays—most notably ‘Amadeus’ and ‘Equus’— managed to be genuinely serious and hugely popular

The obituaries for Peter Shaffer, who died earlier this month at the age of 90 and for whom Broadway is dimming its lights Thursday, were respectful but not effusive. The respect makes sense, since he wrote, among other things, “Amadeus” and “Equus,” two of the most successful plays of the postwar era. The conspicuous lack of wholehearted enthusiasm, however, also makes sense, since Mr. Shaffer, for all his success, wasn’t anybody’s favorite playwright, nor is his work frequently seen in this country nowadays. I’ve reviewed just four Shaffer revivals in the past 13 years, and only one of them, the 2007 West End production...